MOVEMENTS, ETC., OF FRESH-WATER PLANARIANS. 591 



specimens gave the usual positive or negative reaction, or 

 kept their course without change, showing only the local con- 

 traction. The first series which I will report was on an 

 individual which was in a condition of great excitation, 

 moving about with more than normal rapidity, and generally 

 '' stirred up." The results of twenty-three stimulations on 

 this specimen were — 



Expt. I. Positive responses . , 1\ 



Tvr J.- p. Specimen in state of 



JNegative responses . 0,'- ^ 



Indifferent responses . 22J 



A similar experiment with another individual in an 

 entirely normal unexcited state, gliding at a moderate rate, 

 gave the following results : 



Expt. II. Positive responses . 20^ 



AT i- o Specimen in normal 



JNegative responses . 2 V ^ 



Indifferent responses . ISJ 



The striking preponderance of the positive reaction in the 



case o£ the unexcited individual is notable. The same 



individual used in Experiment II was now " stirred up" by 



poking it violently about the dish with a needle for about 



five minutes. It was then allowed to settle into a glide 



which was at a more rapid rate than normal, and another 



series of stimulations was made, with the following results : 



Expt. II r. Positive responses • ^1 



XT i- o Specimen in condi- 



Negative responses . 3 ^ ' . 



T :i-cc i. o tion of excitation. 



Indinerent responses . 8; 



Here, again, the indifferent responses are in excess, and 

 there are practically no positive reactions. The specimen 

 was again " stirred up " in the same way as before, and 

 another series taken. 



Expt. IV. Indifferent responses (trials 

 1 to 11 inclusive) 

 Positive responses (trials 12 



and 13) 

 Negative responses (0) 



Specimen in state of 

 excitation. 



